Process of making soap



Jan- 27, 1942. B, H THURMAN '2,271,406

PfzocEss oF MAKING soAP Filed March 5. 1938 Patented Jan. 27, 1942 rnocsss or MAKING soar Bronxville, N. Y.. assignor Benjamin H. Th

to Refining, Inc., Nevada Reno, Nev., a corporation of Application March 5, 1938, SerIai No. 194,225

4 `(llaims.

This invention relates to a process of making soap, and more particularly to a process of reacting sapcnifiable materials with molten alkalies.

An object of the present invention is to provide a process of reacting saponiiiable material with molten anhydrous alkalies in order to produce anhydrous soap'.

Another object of the invention is to provide a process of producing anhydrous soap and subsequently cooling and rehydrating said soap to any desired water content.

Another object of the invention is to provide l a process of reacting saponiiiable materials containing combined volatile materials with molten alkalies so as to produce anhydrous soap and directly recover said volatile materials from said soap. f

A further object of the invention is to provide a process of producing soap wherein saponiable materials are introduced into a body of molten anhydrous caustic alkali, whereby anhydrous soap is produced. h

A still further object of the present invention is to provide a process of making soap in winch the fatty acid radicals of the resultant soap have a higher degree of saturation than those of the saponiiiable materiaL In accordance with the present invention, saponiflable material is gradually introduced into a body of molten alkali, preferably below the surface thereof, so as to form a Isaponiied mix ture. The process may be carried on as a batch process or a semi-continuous process, and, in seither case, the resulting soap may be cooled and lhydrated to any desired extent.

Also. Vin the case of glycerides of fatty acids, or other esters of fatty acids. vaporizable materials such as glycerine or higher fatty alcohols can be directly vaporized from the soap during the formation thereof, and condensed and recovered.

The attached drawing is a diagrammatical illustration of the present process.

Referring to the drawing: Il indicates a reaction chamber in which the saponification reactions may be carried out. 'I'he reaction chamber is provided with a heating means, such. for example, as a chamber Il surrounding the lower portion of the reaction chamber and adapted to contain a heat transferring medium such as a molten low-temperature-melting alloy or a heated mineral oil. The chamber II may be provided with a vent I2 and a heating device such as a burner I3 for gaseous or liquid fuel for heating 55 (Cl. 26o-417) the material contained in the chamber accurate temperature control of the reaction chamber III is desired, the structure just described is particularly adaptable, but any other suitable means for heating-the reaction chamber can be employed, and also the heating bath contained in the chamber I I may be heated by any other suitable means, such as by electrical heating elements or any conventional furnace structure. The reaction chamber I0 and heating chamber I I are preferably surrounded by an insulatingA cover I 4 in order to maintain the temperature 'substantially uniform throughout the reaction chamber and prevent heat losses.

For batch operation, alkali may be charged directly into the reaction chamber Iil through an opening Il capable of being sealed by a removable closure member I8. Such alkali can be melted directly in the reaction chamber I0 while the closure member IB is removed. or any vaporizable material contained in the alkali may be removed during melting by the vacuum pump II Il. Since .connected to the reaction chamber through a vapor withdrawal conduit IB, condenser I8 and receiver 2li. Even for such batch operation, it is preferred to melt the alkali extemaily of the reaction chamber in a container 2l arranged to be heated by a burner 22 for gaseous or liquid fuel. or any other type' of heating device. The lalkali may be melteddn the receptacle 2|, eitherrin batches or. by intermittently adding into the evaporating chahibef through a heat insulatedp'ip 23 provided with a valve 24 which is preferably' positioned in the heating bath contained in the chamber II, in order to prevent solidincation of alkali in said valve and conse.- quent dilcult operation thereof. The valve 2l may be arranged to be operated by means (not shown) extending externally of the chamber Il.

Baponinahle material may be preheated in a chamber 2l which may phere, if desired, although an open chamber may be employed if temperatures below that which will injure the saponlable material in contact with the atmosphere are employed.' Chamber II may contain a heating coil 21, or any other type of heating device for heating the material contained in the chamber, 2l. The saponiflablemateria] may be delivered into the reaction chamber I0 through a pipe 28 provided with a valve 28. An agitator n is preferably provided in the reaction chamber Il. 4The shaft I I- of the agitator maypass through apacking gland l! and be be closed to the atmosrotated from any suitable source of power through the pulley ll. Or for certain opera where anhydrous condensates are not req superheated steam may be introduced through a pipe $3' to agitate the material in the reaction chamber and assist in vaporization. y

The resulting soap may be withdrawn through a pipe 34 by a pump ll, and delivered into a cooling and rehydratlng chamber 38. Pipe Il is provided with a valve 31, also preferably positioned` in the heating bath contained in the chamber Il, in the same manner as valve 24.

`The cooling and rehydrating chamber 36 is preferably closed to the atmosphere, and provided with an agitator 38 driven from any suitable source of power through a pulley Il. Water in controlled amounts may be introduced into the cooling and rehydrating chamber Il through a piped, and Icooled and rehydrated soap withdrawn from the chamber ll through a pipe Il provided with a valve 42. The cooled and rehydrated soap withdrawn, while still at sumcient temperature to maintain the same liquid, is introduced into a conveyor l! provided with a cooling jacket M so that the rehydrated soap may be cooled to solid form and extruded through the discharge opening of the cover.

Large amounts of steam are formed in the chamber 38 during cooling and -rehydration of the soap. and at least a portion of this steam may be delivered through the pipe Il to the heating coils 31 and utilized for preheating saponiable material, while any steam not necessary for heating the saponiflable material may be exhausted through the pipe 41, or superheated and utilized to` agitate the materials in the reaction chamber.

In carrying out the process of the present invention, the process is started by forming a body of molten alkali in the reaction chamber ID. This body of molten alkali may be formed by introducing alkali directly into the reaction chamber through the opening i5 and melting the same within the reaction chamber. The alkali is, however, preferably melted in the receptacle 2| and then introduced into the reaction chamber, as the step of melting the alkali can then be carriad on simultaneously with a saponifying reacuan within the chamber It.

After the body of molten alkali has been formed in the chamber ID, the saponifiable material is introduced through the pipe 28, preferably below the surface of the molten alkali, by opening the valve 28. The reaction of the alkali and saponiliable material is extremely rapid, and a substantially uniform mixture is maintained by means of the agitator 3l or a current of superheated steam. Since the saponiable material is rapidly converted into soap, the saponiilable material is not subjected to extremely high temperatures for any appreciable length of time, and no substantial decomposition of the saponiable material'is produced. 1f the saponiiiable material consists essentially of glycerides of fatty acids or higher fatty alcohol esters of fatty acids, such as sperm oil, glycerine, or higher alcohols, respectively, are liberated, withdrawn through the pipe I8 and condensed in the condenser is. The vacuum pump i1 is utilized to maintain as high a vacuum as practicable in the evaporating chamber Ill, so thatl the volatile materials are promptly withdrawn and cooled before any appreciable decomposition takes place.

The saponitlable material is gradually introduced into the bodymf molten material in the steam are formed, and, as

reaction chamber I0 until a substantially neutral soap is produced therein. The temperature within the reaction chamber is maintained sumciently high to keep the resulting soap in molten condition. and, since the reacting mass never becomes acid, decomposition of fatty materials'is' minimized.

Substantially exact neutralization may be obtained by withdrawing samples of the reacting mixture from time to time by test conduits (not shown). testing the same, and then adding sumcient saponiilable material to make the reacting mass neutral.

When the molten mass of soap is substantially neutral, it is withdrawn from the reacting chamber I0 and introduced into the cooling and hydrating chamber 16. Water may be added through the pipe Ill, and the mass agitated by means of the agitator 38. Large amounts of stated before, such steam can be utilized to preheat the saponiflable material or agitate the materials in the reaction chamber. When sumclent water has been added to the soap in the chamber 36 to reduce the temperature thereof below the boiling point of water. additional water can be added to bring the soap to any desired degree of hydration. Since commerclal bar soap or powdered soap contains between approximately l0% and 30% water, such a commercial soap may be prepared in the chamber 1B. The degree of hydration of the soap in the chamber 38 may be determined by withdrawing samples thereof from time to time through test conduits (not shown).

By maintaining the hydrated soap in the chamber .all at an elevated temperature, for example a temperature in the neighborhood of 212 F. or higher, it can be maintained in the liquid condition and withdrawn through the pipe Il by opening 4the valve l2 so as to discharge the soap into the conveyor by which it may be cooled and extruded, as before described. I! it is desired to produce a soap having a relatively low degree of hydration, the chamber le may be operated under pressure by partially closing the valves shown in pipes and I1, so that a higher temperature than that corresponding to the boiling point of water at atmospheric pressure may be maintained in the chamber Il, in order to maintain the soap in liquid condition.

The process may also be carried on in a semicontinuous manner. After a body of substantially neutral anhydrous molten soap has been formed in the reaction chamber Iii, it may' be partially withdrawn and additional molten alkali introduced through the pipe 2l into the chamber Il. Additional saponiiiable material may be introduced gradually through the `pipe 2l until another body of substantially neutral anhydrous molten soap has been formed, which is again withdrawn. and then additional melted alkali added, etc. Thus, additional alkali may be melted during the reaction period in the reaction chamber Il and at the same time the previous body of molten anhydrous soap may be cooled and rehydrated ln the chamber 36. It is preferred to maintain a vacuum at all times in the reaction chamber il. and, by utilizing the pump II, molten anhydrous soap may be withdrawn from the reaction chamber while the vacuum is maintained. in the reaction chamber.

While any solid alkali capable of being melted without decomposition may be employed as a, saponifying reagent, it is preferred to employ substantially anhydrous caustic alkalies. Anhydrous caustic soda is the preferred saponifying reagent,

since it melts at a lower temperature than caustic potash. By employing caustic alkalies, no substantial amount of incondensable gases is liberated therefrom in the evaporating chamber, as would Abe the case if carbonates were employed. By employing anhydrous caustic alkalies as the saponifying agent and glycerides as the saponifiable material, substantially anhydrous glycerine vapors are liberated and can be Withdrawn through the pipe IB and condensed in the condenser I9 to produce substantially pure anhydrous glycerine. A similar operation can be carried on with higher fatty alcohol esters of fatty acids, such as sperm oil, and dry higher alcohols recovered in the condenser I9. When employing fatty acids or other saponiable acids, water vapors will be liberated in the reaction chamber ifi, and these can bo condensed in the condenser i@ so as to enable the vacuum pump il' to main@ tain a relatively high vacuum. in the reaction chamber il?.

The temperature in the reaction chamber il must be at least nigh as the melting point oi the alkali employed. when employing anhydrous caustic soda, this temperature must be at least 604 F., while, if anhydrous caustic potash is ein-- played, the temperature must be at least '716o F. Somewhat higher temperatures, ranging up to 625 F. for a caustic soda or '135u F. for caustic potash, are preferably employed in order to inm sure that the alkali remains in liquid condition. These temperatures are suiciently high to ins sure that the resultant soap will be in molten condition, as anhydrous soap is molten at temperatures between approximately 450 F. and 620o F., depending upon the type of saponiiable material employed.

By employing a relatively small reaction chamber, each soap making operation may be carried on in a relatively short period of time so that the soap is not subjected to the high temperatures for extended periods of time. Thus, Pyrolytic decomposition of the soap due to heating for long periods of time can be avoided, and also4 the so-called Varrentrapp reaction can be minimized. In certain instances, it is desirable to carry .on the Varrentrepp reaction to a desired extent, and this can be accomplished by maintaining the soap in the reaction chamber for longer periods of time. r'Ihis reaction is not a pyrolytic decomposition of the fatty material, but is a deinlte chemical reaction in which a molten caustic alkali reacts with unsaturated fatty acid radicals to liberate hydrogen and produce fatty acid radicals of greater saturation having a lesser number of carbon atoms than the original unsaturated fatty acid radicals. Thus. the Varrentrapp reaction produces a harder and more stable soap.

It is apparent that anhydrous cooled soap may be produced by eliminating the chamber 88 and delivering the molten anhydrous soap from the reaction chamber Ill directly to the cooling con- Thus the present invention provides a process r of producing either anhydrous or hydrated soap directly from saponiable materials and molten alkali. It also `provides for therecovery ot volatile materials such as glycerinev liberated by ing point oi thn the saponicatlon of saponlilable materials containing combined volatiles, and the volatile materials may be recovered in substantially pure liquid anhydrous form. Substantially pure neutral soap is produced, and the character of this soap may be controlled by varying the time the soap remains in the reaction chamber I0 at the high temperatures contemplated.

While the preferred embodiments of this invention have been disclosed, it is to be under-- stood that the details thereof may be varied Within the scope of the following claims.

I claim as my invention:

l. The process of producing soap, which com prises, forming a body of molten substantially anhydrous alkali in a closed chamber out oi' contact with the atmosphere and gradually inw 'troducing saponiable materials into said body ally an 1forlned, and ooling ...e e contacting .the same xiti i compriais, fori n tlally anhydrous a body out ci Contact with. ally introducing saponifiable materie nto said body while maintaining the temperatures of said body above the lneltu snbstantiallv anhydrous soap produced, continuing the addition oi said saponiiable material until a body of substantially neutral molten anhydrous soap is produced, thereafter adding Water to said body of molten soap, and withdrawing steam therefrom until the soap is cooled and a deinite amount oi water remains therein.

3. The process of making soap, which comu prises, introducing molten anhydrous caustic alkali into a reaction chamber to form a body of molten anhydrous alkali therein, gradually introducing sufficient saponifiable material into said reaction chamber to cause the same to react with said alkali and produce substantially neutral soap, maintaining a vacuum in said reaction chamber during the introduction of said saponifiable material. maintaining the temperature in said reaction chamber suillciently high to cause the resultant soap to be in molten anhydrous condition, withdrawing a portion of said anhydrous soap from said reaction chamber, introducing additional anhydrous molten alkali, and successively repeating said process.

4. The process ot making soap and recovering substantially pure and anhydrous glycerine, which comprises, forming a body of molten anhydrous caustic alkali in a reaction chamber, producing a vacuum in said chamber, gradually introducing saponiflable materials consisting essentially of glycerides of fatty acids in an amount suiilcient to produce substantially neutral soap. heating said reaction chamber during the formation of said soap to a temperature to maintain said soap in substantially anhydrous molten condition and liberate glycerine vapors, withdrawing glycerinevapors from said reaction chamber! and condensing the same to form liquid. substantially anhydrous glycerineNat a rate sufficient to maintain said vacuum in said reaction chamber.

BENJAMII?? H. THURMAN. 

